Signaling system



Oct. 1,1929. P. MERTZ vSIGNALING SYSTEM Filed Jan. 7, 1928 4Sheets-Sheet 1 l all LS Nw INVENToR. I? Meli/z fw A TTORNEY Oct. 1v,1929. P. MERTZ SIGNALING SYSTEM Filed Jan. '7, 1928 4 Sheets-Sheet w@@123456789@ mz/W f acde Zolar IN VEN TOR. P. Malz.

ATTORNEY Oct. 1, 1929. P. MER-rz ASIGNALING SYSTEM 4 `Sheets-Sheet CATTORNEY Oct. 1, 1929. P. MERTZ SIGNALING SYSTEM Filed Jan. 7, 1928 4Sheets-Sheet 4 ,S e @,wfqgwnmmmmnmmwwmww S. 0 Y T E l v y y, N u N E R lV 0 NMWWT -..i T L xl.. l z w v l l c a w t l v I l l l u 1| t S w) F@M4 a, z .s& i 0Il n u .d.w f M I-.. mm/wAu im .l S l @mw f @Wf [Uf L ll. vnr. h :J I I Y l l I I I l Y I I I I I l x x l l l l Il 0J e cf. 1 yy y y l l l w l aw y x x l l l I I w d l I l y R 5 c y b I a a .m d l 23 2 5 a. 5 .2 ,5 7 d 9 0 l 2 l 2 3 3 4 5 6 o 9 0 .1 1 wmmmmmmm mmwmmmmo,.L 0J u .m .IMJ W WJ 1 f .W Z .WJ n n n n u .M M u n. u M COU M j C 1 fu u n m E M UM d E m m a @pw m TJ W wwwe C w v 15 my invention toprovide Patented ct. I1', 1929 I l UNITED STATES PATENT o'F-ElcE PIERREMERTZ, OF BELLEBJOSE MANOR, YORK,

ASSIGNOR TO AMERICAN TELE- sTGNALING sxsrE-n application mea January 7,192s. serial no. 245,129.

vIn the transmission of intelligence by signaling, the capacity of asystem will depend on the number of signal elements per second (halfthis quantity is commonly called the 5 dotting speed or the signalspeed),and on the number of ossible kinds of signal elements that can ediscriminated'in an interval for one signal element. 'In some cases, itwill be desirable to change a message so as better to adapt it fortransmission over available apparatus by diminishing 'the signal speedand at the same time increasing thel numberof possible distinguishablesignal elements, or vice versa. It is an object of for making such achange; that is, to change the number ofsignal elements the propercorresponding change in the number of distinguishable signal `elementsthe other way. This object and othei` objects of my invention willbecome apparent on consideration of the following discussion of twospecific 'cases of practice according to the-invention, which I havechosen for presentation here by way of example. Referring to thedrawings, Figure 1 is'a diagram of apparatusthat may be employed in thepractice of my invention under certain circumstances; Figs. l and 1b arediagrams to accompany Fig. 1; Fig. 2 is la coordinate diagram showinghow the various parts of the apparatus of Fig. 1 operate for a train ofsignals; Fig. 3 is a diagram of apparatus for a-case somewhat differentfrom Fig. 1; Figs. 3a, 3*?, 3c and 3d are diagrams ancillary to Fig. 3;and Fig. 4 is a coordinate diagram for the successive stages ofoperation of the various parts of the apparatus of Fig. 3.

In a signaling system in which successive signal elements are sent inrespective equal time intervals, say n such-intervals per second, 12,/2is called the signal speed. In each signal interval. of one nth of asecond the signal element must have at least two possibledistinguishable characters, and may have more. Suppose for example thatthese distinguishable signal characters are current magnitudesconsidered .algebraically so 9 measure are 4deemed to be of differentmagper second one way and make` paratus 52. The transmittin thatpositive and negative currents of equal nitude. Let the number of suchdistinguishable magnitudes be C. Then, for a given amount ofintelligence te be transmitted in a given time, the condition isC=constant. It will readily be seen that if a certain signal speed is tobe halved, then the number C must be squared; if the signal speed is tobe reduced to one-third, then C must be cubed, etc. A

In the example of the invention re resented 1 and 2, a signal train orwhich C=2 and n has a certain value is converted for transmission into asignal train in which C=4 and n is half said value. Such an initialsignal train is represented by sub-figure 1 in Fig. 2 (Fig. 2 (1)),where each signal element is either plus a unit of current or mins aunit of current. This signal train is transmitted inthe form shown inFig. 2 (7) where there are only half as many signal elements in the sameperiod of time but each element may have any one of four differentcurrent values represented as -3, 1, +1, +3.

At the receiving end, the signals of the character shown in Fig. 2 (7are converted 75 back to the initial form an manifested as shown in Fig.2 (15). l

The message to be sent from station west in Fig. 1 is punched in thetape 50, shown at the left of Fig. 1, which is driven bv theapdistributor T 1s also driven in s chronize relation with the tape 50,so t t the distributor arm 53- 54-55 makes one cycle for four successivepositions of the tape that is, the tape 50 ste s ahead one position whenthe `arm is up, wen to the left, when down, and when to the right.

At the receiving end, the arm of the receiving distributor R moves insynchronism with the sending arm at T. This synchronism may be eiectedby suitable, well-known means not here disclosed. Further details ofstructure and the mode of operation of the apparatus shown in Fig. 1will be made clear in 95 the following description of the cycle ofoperations for transmitting several successive signal elements.

Starting with the distributor arm at T in the up position, call theensuing signal in- 10 tervals a, b, c, etc., and the correspondingquadrants swept over by the signal arm I, II, III and IV. Let the signalelement in the period a be a spacing element, represented at ain Fig. 2(l) as a unitof negative current. This means that negative battery isapplied through the tape 50 and over the conductor 51 to the distributorring 36, brush 55, segment of ring 37 and relay winding 61, whosearmature is accordingly put to negative battery. When the brush 53 makescontact with the end of the segmental ring 32 in quadrant I, a holdingcircuit is completed from this negative battery through the relaywinding 61', ring 32 and brush 53 to ground, and this holds through theremainder of quadrant Iv and all of guadrants II and III. The pick-upcurrent through winding 61 already nientioned is represented by the area66 in Fig. 2 (2) and the holding current through winding 61 isrepresented by the shaded arca 67 in the same figure. Thus. the impulsein time interval a is stored in relay 61-61 through the succeeding timeintervals b and c.

i The pick-up current through relay winding 61 is interrupted when thedistributor arm passes from quadrant I to quadrant II at the end ofsignal interval a and the beginning of interval b. At this instant, thebrush 54 engages the end of the lower segment of ring 35 and puts to therelay 64 the negative battery associated with relay 61-61, throwing itsarmature to the right, as represented in Fig. 2 (5). Also, at this sameinstant, the tape 50 steps forward one lstage and cuts ofi:l negativebattery and applies positive battery to the conductor 51 and thencethrough ring 36, brush 55, segment of ring 37 to relay winding 62. Itsarmature is accordingly thrown up, thus applying positive batterydirectly to the windings of-relay 65-65 and moving its armatures to theleft, as indicated in Fig. 2 (6). This puts one unit of negative batteryon the line, as indicated in Fig. 2 (7). The pick-up current through therelay winding 62 continues during and only during the traverse ofquadrant II by the arm of distributor T, but when the brush 53 engagesthe end in that quadrant of a segment of ring 31, the holding circuit iscompleted from positive battery through the relay winding 62 to ground;and

this holding circuit is maintained until the end of time interval c,that is, when the distributor arm passes from quadrant III to quadrantIV. The pick-up current in the Winding 62 is represented by the area 68in Fig. 2 (3), and the holding current in winding 62 is indicated by thearea 69.

Thus, it will be seen that the .two successive signal elements a and I),determined by the tape .50, determine respectively the operation ofrelays 64 and 65-65 throughout the double time interval 5 0, andaccordingly determine the current magnitude on the line through thatdouble interval b-c. During the two successive intervals a and b, thereis actually represented in Fig. 2 (1) These four different combinationswill determine, respectively, the positions of the armatures of relays64 and 65-65 so as to put units of battery on the line as follows: +3,+1, 1, and 3. Thus, for each possible combination of two successivesignal elements a and b in the tape 50 there will be put on the line acertain corresponding magnitude of current throughout the time intervalsb and c.

When the arm of distributor T passes from quadrant II to quadrant III,neither relay 61 nor 62 can be utilized because both of these must storeimpulses throughout quadrant III. In quadrant III or time interval c,the signal impulse is negative, as represented in Fig. 2 (1), andaccordingly negative battery is applied through the tape 50, overconductor 51, through ring 36, corresponding segment of ring 37 andrelay winding 63, whose armature is accordingly put on negative battery.This pick-up current in relay winding 63 is represented by the area 76in Fig. 2 (4). Vhen the distributor arm reaches the middle of the thirdquadrant, the brush 53 engages the segment of ring 33 and puts negativebattery through the relay winding 63', ring 33 and brush 53,to ground.The current that {iows is a holding current for the relay 63- 63 and isrepresented by the shaded area 77 in Fig. 2.

When the distributor arm passes from quadrant III to quadrant IV, theholding circuits .for relays 61-61 and 62-62 are broken, and thecorresponding circuits heretofore described for relays 64 and 65-65 arebroken. At once, a circuit is closed from the negative battery withrelay 63-63 through the upper half of ring 35, brush 54, ring 34 and thewinding of relay 64. thus throwing (or holding) its armature to theright. This represents the effect of the impulse that was storedinitially in relay 63-63'. Also, when the distributor arm passes fromquadrant III to quadrant IV, the tape 50 steps forward one position andcuts o negative battery and applies positive battery to the conductor51, as represented atl d in Fig. 2 (l) the circuit is made through ring36 and the corresponding part of ring 37 and relay winding 62, causingits armature to put positive battery to the relay windings 65 and 65',thus throwing (or holding) their armatures to the left.

With the description that has gone before, it will readily be seen howthe impulses for time intervals c and d, now set up respectively inrelays 63-63 and 62-62, will be stored and held throughout timeintervals d and e and will determine the operation of relays 64 and65-65, respectively, and determine the magnitude of current on the linethroughout the double period d--e.

maas

Thus, each successive pair of two-value elements of the original signaltrain is converted into a single four-value element that is operativeduring the time interval of the second element of the pair and the firstelement of the next succeeding pair.

At the receiving end, the impulses on the line go through the threewindings 71. I and 73 of respective relays. Associated with the winding71 is a biasing winding 71 with two units of negative current so thatthe critical current value in winding 71 for the operation of this relayis +2 units of current; in other words, the armature of relay 71-71 goesup for currents above +2 units and down or currents less than +2 units.The relay 72 is unbiased and the relay 7 3,-7 3' is biased y oppositelyto 71-71.

' relay windin g Following out the specific cycle of operations alreadytraced at the sending end, the current ion the line for thedoubleinterval 5 0 is one unit negative, as represented in Fig. 2 (7).Accordingly, throughout the interval b-c the relay armatures will bedown for 71 71, downlfor 72, and up for 73-73, as shown in Fig. 2 '(8,9, 10). Thus, the negative battery associated with relay 72 will beapplied toA rings 43 and 45 in multiple over the respective conductors78 and 79, as shown in' Fig. 2 (11, 12). The currents in these twoconductors correspond, respectively, with those in relays 64 and 6,5-65at the sending end, except that the current in 79 is reversed i ascompared with 65-65.

The conductors 78 and 79 are connected, re-` spectively, throughout timeperiod b-c to the appropriate batteries through the armature contacts ofrelays 71-71, 72 and 7 3 7 3f and for a brief time at the middle of thisperiod 5 0, the distributor effects connections completing the circuitsfrom said batteries through to respective relays 7 4 7 4 and-75'- aswill be pointed out presently. This is according to approved practice bywhich at the receiving' end the signals are picked o at the middle orapproximate peaks of the incoming' signal impulses.

When the receiving arm of the receiving distributor R has nearlycompleted quadrant II, the said two branch circuits will be completed,respectively, by brush 5.7 engaging the lower segment of ring 44 andthus connecting through the relay winding 74, and'b'y brush 58connecting, with the segment of ring 46 and thence through the relaywinding 75. Accordingly, the armature corresponding to 74 will engagethe .negative battery and the armature corresponding to relay winding 75will engage positivebattery. This arrangement of polarities compensatesfor the reversal shown and mentioned for F ig; 2 (12) as compared withFig. 2 `(6). The current from negative battery' associated withrelay'winding 74 will flow through lower segment of ring 48, brush 59,

lductor 86, segment of ring 48,

ring 47 and the polar sounder 80. The pickup current in the Winding 74is represented by the unshaded area at 8l in Fig. 2 (13). Acorresponding holding current through the windin 74', that flows whilethe brush 56 egiga es t e ring segment 41, is represented y thg shadedarea 82 in Fig. 2 (13). The current through the polar sounder 80, thatflows while the brush l59 engages the lower segment of the ring 48, isrepresented by the area 83 in Fig. 2 (15).'

At the same time that current began to flow in the winding 74,. as justdescribed, it also began to flow in the winding 75 from the negativebattery associated with relay winding 72, over the conductor 7 9., ring45, brush 58 and ring segment 46. This current is represented by theunshaded area 84 in Fig. 2 (14). Its effect is to put positive batteryto the corresponding armature from which the two conductors 85 and 86extend in multiple, but no circuit will be closed on either of themuntil the brush 56engages ring segment 42 at the instant of transitionfrom quadrant II to quadrant III. Thereupon, a holding current Howsthrough the winding 75. This lasts until the distributor arm reachesnearly to the end of quadrant IV and is represented in Fig. 2 (14) bythe shaded area 87.

When the distributor arm has traversed nearly the whole of quadrant III,its brush 59 engages an end of a segment of ring 48 and closes a circuitfrom the positive battery aS- sociated with relay 75-75 through conbrush59, ring 47 and polar sounder 80, thus giving a positive signal impulsein the polar sounder 80 wlich) is represented by the area 88 in Fig. 215 .In view of the foregoing description, it will be readily understoodhow further successive double period signal impulses received from theline are analyzed and separated to the relays 74-74 and 75-75 and thencetaken off in succession to the polar sounder 80.

In the foregoing example of practice according to my invention, We dealwith a line which is best adapted for a certain comparatively slowsignal speed and with four possible distinguishable signal elements ineach signal interval, together with transmitting and receiving apparatuswhich is most advantageously operated at double the signal speed of theline and with only two possible distinguishable signal elements persignal interval. These twov signal speeds are commensurable and therelation between them and the other factors involved is shown in theequation (lbconstant by the fact that starting with C=2 and doubling Cand halving n preserves the equality with the constant unchanged. Butsuppose we have aline in which the signal speed is not so simplyreparatus.' For example, suppose that in the terminal apparatus thesignal speed is a certain value for two distinguishable signalcharacters and that we want to operate at a signal speed reduced justenough to take advantage of three distinguishable signal characters onthe line. Accordingly, from the fundamental equation heretoforementioned, we should have 2=)/r where o will be the ratio ofthe signalspeed of the terminal apparatus to the signal speed on the line. Solvingthis equation for r, the result is obtained that 1:1585 approximately.This ratio is incommensurable and shows the practical impossibility oftransforming the signals exactly in the case supposed. It is possible,however, to secure automatic transformation at the expense of a slightlylower ratio in signaling speeds, that is, by wasting the availablesignaling facilities in some small degree. We might choose an integralratio approximating in some degree to the ratio r (and necessarily lessthan 1'), but the next lower integer is 1,' which represents notransformation whatever of the signal. It is possible, however, totranslate the signals from the original to an intermediate forminvolving an integral ratio in signal speeds and then to translate againfrom the intermediate to a third form involving another integral ratioin signal speeds so that the resultant combination of the two integralratios will approximate to and be slightly less than the desired ratio1'. For example, starting with 0:2, we have 2=constant' where half of nis the signal speed. Evidently 8/3=same constant where now the number'of distinguishable signal elements is increased from 2 to 8 and thesignal speed is decreased from half Vof n to half of frz/3. Thisexpression 3"/3 is approximately equal to but somewhat less than 32"/3,and comparing the initial expression 2 with the final expression 32/3 wehave 7=1.5 which approximates roughly to the ideal value mentionedheretofore, namely 1=1.585. Figs. 3 and 4 are based on thisapproximation, 1=1.5; the apparatus is shown in Fig. 3 and the operationof its parts is shown in time sequence in Fig. 4. It would be possibleto secure a closer approximation to this ideal ratio at the expense ofgreater complexity in the apparatus.

The general principle of operation involves dealing with groups of threesuccessive signal elements, (each of two possible values) as representedin Fig. 4 (1); and for each such group putting on the line two signalelements (each of three possible values), as represented in Fig. 4 (12).

As in the case of Figs. 1 and 2, the transmitting distributor T and thereceiving distributor R operate in synchronism, by virtue of means nothere disclosed, but well known and available. Each revolution of adistributor arm takes place in six time intervals for the message in itsinitial and inal form, as shown in Fig. 4 (1) and Fig. 4 (29). I referto the corresponding angular divisions of the sweep of the distributorarm as sextants I to VI, as indicated in Fig. 3a. Three successiveimpulses are stored in the relays 101, 102, 1,03, and the next threesuch impulses are stored in the relays 104, 105 and 106. While theseimpulses are being stored in the second set of relays, two successiveimpulses each one and one-half times as long as an initial impulse arebeing put on the line through the transmitting distributor T, asdetermined by the stored impulses in the first set of relays; andwhereas the initial impulses are each of only two possible values, theimpulses put on the line are each of three possible values.

In the case considered in connection with Figs. 3 and 4, the two valuesfor each initial impulse are zero and a positive unit of current. Theseimpulsesv go from the transmitter over conductor 100, through ring 119,brush 109 and corresponding-segment of ring 120 to the respectivelyconnected relay windings 101 to 106. Accordingly, the first impulse ofFig. 4 (1), which is of Zero current as represented at 110, leaves allthe armatures for relay 101 on their back-stops, as indicated in Fig. 4(2). The second signal impulse at 121 in 4 (1) puts the armatures forrelay 102 on their front-stops, as indicated at 137 in Fig. 4 (3) and soon for all six relays 1-01 to 106, as shown in Fig. 4` (2, 3, 4, 7, 8,9).

Holding circuits as shown in dot-ted lines in Fig. 3 are provided forthe respective relays and are not energized or are energized accordingas the relay armatures remain on their back-stops or are drawn to theirfrontstops. Thus, for example, at the middle of the second signalimpulse 121 of Fig. 4 (1), the brush 107 engages the segmental ring 115and grounds the positive battery associated with relay 102, so that itscurrent iiows through auxiliary winding 102 and holds the relay closedfrom the middle of sextant-II until the end of sextant VI, as shown bythe shadedarea 138 in Fig. 4

Thus, the first three impulses of Fig. 4 (1) are set 11p-initially inrelays 101, 102 and 103, respectively, as the distributor arm sweepsthrough sexta-nts I, II and III and remain stored ,as it goes on throughsextants IV, V and VI. These three relays 101, 102 and 103determineeight different combinations for their armatures from which thetwo conductors 122 and 123 lead away.- The eight different combinationsmentioned 4are indicated symbolically in Fig. 3d. Each combinationdetermines one of three different current magnitudes to be applied toeach of the conductors 122 and 123, namely, plus a unit of current,zero, or minus a unit of current. Three different magnitudes on eachlll - the conductor 122 from the line and conductor 122 and 123 givenine combinations for both conductors, These are represented in theright-hand part of Fig. 3". A sim le systematic arrangement of thearmatures or the relays 101, 102' and .103 so that the eight dlii'erentcombinations therein will determine correspondingly eight of the ninepossible combinations of current magnitudes in conductors 122 and 123 isas shown in Fig. 3. It will at once be apparent in Fig. 3 that many ofthe contacts are superfluous, and the practical arrangement of thearmature connections shown in Fig. 3 is correspondingly simplifiedmechanically as compared with Fig. 3. Also it will be noticed that oneof the nine possible line signal combinations of Fig. 3, namely -l-,isnot utilized. This represents wasted line capacity due to theapproximation involved in chan ng from C=2to C=3 as pointed out heretoore.

Accordingly, at the end of sextant III, one of eight different possiblecombinations has been set up in relay windings 101', 102 and 103', andany one of eight different combinationsl of three current magnitudeseach .has been determined in the-positions for the armatures of theserelays for application to the conductors 122 and 123, as indicated inFig. 4v (5, 6). When brush 108 passes from sextant III to sextant IV, itconnects conductor 122 through ring segment 118 and ring 117 to the line124, and, through the ensuing 90 travel of the distributor arm,

-current of one of the three possible magnitudes goes over theline, asindicated in Fig. 4 (12). At the middle of sextant V, the brush 108passes from one segment of ring 118 to the next segment, thusdisconnecting connect ing conductor 123 `to the line and again duringthe next 90 travel of thevdistributor arm one of three possible currentmagnitudes is applied to the lineas indicated in Fig. 4

v 12) and as determined by the positions of t e armatures of rela s 101to 103.`

Thus, for the initialys'ignal train shown in Fig. 4 (1) with vthreesuccessive impulses, a, c, each of two possible values, there are put onthe line two signal impulses each of three possible values, as shown inFig. 4 (12) While the separate impulses in relays 101 to 103 are beingsent in sextants 'IV to VI,

the initial signal impulses d, e, f are being set up and stored inrelays 104 to 106, as indicated in Fig. 4 (7, 8, 9), and these de-'termine one-of three battery strengths applied respectivel to conductors122 and 123', as indicated in ig. 4 (10, 11), and two successive lineimpulses are sent accordingly as the distributor arm sweeps throughl thesucceeding three sextants I, II and III. Thus, the' signal impulses areregrouped and transformed and put on the hne as indicated in Fig. 4.-(1)to (12).

At the receiving end, these impulses are delivered to the windings 127and 128 of respective polar relays biased respectively with a unit ofnegative current and a unit of positive current in the respectiveauxiliary windings 127 and 128. Accordingly, these relays will beoperated at the current levels shown in Fig. 3", and as indicatedin`Fig. 4 (13, 14). It will be apparent from the diagram of Fig. 3 thateach signal impulse received from the line in the relays 127 and 128will determine one of three diierent possible combinations of positionsfor their armatures whichcombination will become effective in the relaysof one of the four pairs of relays 129 and 130, 131 and 132, 133 and 134or 135 and 136 when the circuit of such pair of relays is groundedthrough conductor 171, 172, 173 or 174, respectively; We have alreadyseen how the three initial signal impulses a, b and c of Fig. 4 (1)determine the two successive line impulses in the time interval d-e-ffin Fig. 4 (12). The first of these two line impulses, being zero, putsthe armature of relay 127 down' and the armature of relay 128 up, asindicated in Fig. 4 (13, 14), whilethe brush of the receivingdistributor R sweeps over sextant IV and the first half of sextant V. Atthe middle of this range of 90, the short segment of ring 155 (at thelower right) is grounded by brush 141, thus putting1 the batteryassociated with relay 128 throug the winding of relay 134, but leavingthe battery with relay 127 on open circuit, so that the winding of relay133 is not energized. Accordingly7 the armatures of relay 134 areattracted to their front-stops, but those at 133 are left on theirback-stops. At the mid dle of this 90J range, the brush 141'engages theend of ring segment 152 and closes a holding circuit (shown dotted)through to the end of the time interval z'. Thus, the engagement of thebrush 141 with the short ring Segment 155 determines tlie energizationof relays 133 and 134 through from about the v middle of time interval dto the end of time interval i, as indicated in Fig. '4 (22, 23).

Similarly, the next following impulse in the line during the last halfof time interval e and all of f determines a position for the armaturesof relays 127 and 128, and impulses are picked olf, accordingly by brush141 from the segment of ring 155 in sextant VI, thus determining thepositions of the armatures of relays 135 and136, as shown in Fig. 4 (24,25)',

and so on for succeeding line impulses, the, Y next one being stored inrelays 129 and130,

(Fig. 4 (15, 16)) and the next after that relays 131 and 132 (Fi 4 (17,18)).

The two signal impu ses on the line in the time interval d-cas shown inFig. 4 (12) accordingly determine, at the end of that time interval, thepositions of the relay armatures ofthe relays 133, 134, and 136, andthus determine whether zero or positive battery shall be applied to eachof the three conductors 158, 159 and 160, as indicated in Fig. 4 (26,27, 28). Thesev three conductors are connected respectively to segmentsof ring 157 in sextants I, II and III and hence, as the brush 142 sweepsover these three ring segments, it puts these batteries of either zeroor positive value successively to the sounder 166 and gives signalelements accordingly in time intervals, g, h, i, as shown in Fig. 4 (29)corresponding to the initial signal impulses a, b, c, shown in Fig. 4(1). Similarly the initial signal elements at the sending end in -t-imeintervals d, c and f are eventually stored so as to determine thebattery strengths put to respective conductors 161, 162 and 163throughout period j-c-Z, as shown in Fig. 4 (19, 20, 21), and in therespective intervals y', k, Z, impulses are taken in succession from thesegments of ring 157 through brush 142 and ring 156 to sounder 166 whichis actuated as shown in Fig. 4 (29):

I claim:

1. In the transmission of signals consisting of a sequence of signalelements of equal duration and a certain deiinite number of suchelements per second, the method which consists in increasing the numberof signal impulses per second, making them of equal duration andcorrespondingly decreasing the number of recognizable characters foreach impulse and transmitting the impulses accordingly.

2. In the transmission of signals consisting of a sequence of signalelements of equal duration, and of a certain definite number per second,the method of changing the signals better to adapt them for transmissionover a' part of the transmitting system, which consists in changing thenumber of signal elements per second in the signal train and cor.-respondingly changing the duration of each impulse, making the impulsesof equal duration and correspondingly changing the number ofrecognizable characters for each impulse.

3. In the transmission of a sequence of signal elements of equalduration each having any one of several recognizable characters, themethod which consists in transforming such sequence to another sequencehaving a different number of signal elements per second of equalduration and an inversely dif-` ferent number of recognizable charactersfor each signal element.

4. In the transmission of a sequence of signal elements, the methodwhich consists in converting a signal train from n signal elements persecond of equal duration, each having C recognizable characters, to asignal train having a number dltferent from n of -signal elements persecond of equal duration and a number correspondingly different from Cof recognizable characters for each signal element.

5. In the transmission of signals over a system having two differentparts, the method which consists in transmitting through one part at thebest signal speed and with the optimum number of distinguishablecharacters per signal element for that partthe signal elements being ofequal duration, then between the two parts converting the signal trainto the best signal speed and the corresponding optimum number ofdistinguishable characters per signal element for the remaining part ofthe system, the signal elements being of equal duration, andtransmitting therethrough' accordingly.

6. In the transmission of a train or" signal elements at a certainsignal speed and with -a certain number of distinguishable charactersfor each signal element, the method which consists in storing andsuperposing successive signal elements and transmitting other signalelements at less si-gnal speed but with a greater number ofdistinguishable characters for each element.

7. The method of signaling, which consists in storing successive signalimpulses in ditferent relays and transmitting over the line a group ofsuperposed eiects determined by said relays.

8. The method of signaling, which consists in cumulating the successivesignal elements of ay group of signal elements and sending a singlesignal element of 'distinguishable character corresponding to thecombination of signal elements in such group. A

9. In the transmission of a train of signal elements, the method whichconsists in reducing the number of signal elements per second andcorrespondingly increasing the number of distinguishable characters foreach signal element.

10. In the transmission of a train of signal elements, the method whichconsists in storing several successive signal elements and then sendinga single signal element distinguishably determined in character by thecombination of stored initial elements.

1,1. The method of signaling over a system in two parts on ditferentcommensurably related signal speeds with the signal elements of equalduration in the respective parts, which consists in converting thesignal train between the two parts from the one signal speed to theother, at the same time makinga the one part into a corresponding signaltrain so adapted for the other part.

13. In combination, means to generate a train of signals of elements ofequal duration at a certain signal speed. and of a certain number ofdistinguishable characters per signal element, means to convert fromsuch train of signals to another train of different signal speed and ofelements of equal duration and correspondingly different number ofdistinguishable characters per signal element, means to transmit theconverted signal train, and means at the receiving end to convert backto a signal train corresponding to the initial signal train;

14. In combination, means to produce a train of signal impulses, relaysin which to store thema distributor between said means and said relays,a line, and means to put a second.\set of impulses on said line, eachcorresponding to a set of separate impulses in the said relays, said'distributor comprising means to determine the character of said impulsesfor the line according to the combination of impulses stored inthe saidrelays.

15. In combination, means to produce a train of signal impulses, relaysin which to4 store them, a distributor between said means and saidrelays, a line, means to put a second set of impulses on said line, eachcorresponding to a set of separate impulses -in the said relays, saiddistributor comprisingmeans to determine the character of said impulsesfor the line according to the combination of impulses stored in the saidrelays, storing relays at the receiving end and a distributor at thereceivin end to determine the operation of said re ays'according to thecharacter of the received signal impulses and distribute spccessiveimpulses to an indicator accordingly.

16. In "combination, transmitting apparatus, a line and receivingapparatus, means between the transmitting apparatus and the line toconvert a signal tram of signal elementsof equal duration from onesignal speed to another train of signal elements of equal duration andfroma cor-responding number of distinguishable signal elementstoanother, and means between the line and the receiving Y aplparatus toeffect the inverse conversion ereby the ultimately received signal trainwill correspond tothe initially sent signal tra-in. Q

17. Means to convert a train of signal impulses vof a certain number nper second and a certain number C of distinfruishable characters foreach impulse to actrainin which L these numbers aredi'er'ent subjectapproximately to the condition thatCn= constant.

. In testimony whereof, I have signed m name tothis specification this6th day of.

January, 1928,

PIERRE MERTZ.

